Apparatus for consuming finely divided fuel



3 w. B. CHAPMAN 1,969,501

APPARATUS FOR CONSUMING FINELY DIVIDED FUEL IN VEN TOR.

BY A TTORNEYS.

2 Sheets-Sheet 2 W. B. CHAPMAN Filed Sept. 6. 1928 APPARATUS FOR CONSUMING FINELY DIVIDED FUEL Aug. 7, 1934.

INVENTOR.

M QMATTORNEYS Patented Aug. 7, 1934 UNITED STATES PATENT GFFEQE APPARATUS FOR CONSUMING FINELY DIYIDED FUEL William B. Chapman, Jackson Heights, N. Y. Application September 6, 1928, Serial No. 304,321

4 Claims. (Cl. 110-28) The invention relates to the burning of finely divided fuel, more particularly solid fuels, to obtain either gasification resultingin high CO content, or-complete combustion, the extent to which CO is formed dependingupon the proportion of air which is fed in.

One object of the present invention is to enable a clean tar-free gas to be made while avoiding certain di-fliculties which heretofore have been encountered in-attempts to-make a gas of this nature; that-isto say, it has been known, that underfed and downdraft. firebeds .have certain advantages in obtaining a clean gas, due to the fact that the volatile tarry matteris driven off first and then passes through the hot bed of coke which makes up the remainder of the firebed, thus breaking upthe tarry gases. Underfed and also down-draft firebeds, howevenrequire a considerable excess of air-if the fixed carbon of the fuel is to be at all completely consumed and are therefore unsuitable for the manufactureof a. combustible gas, while firebeds of the top: feed and up draft type ordinarily used for making a combustible gas, although they consume the fuel quite completely, do not have the advantages of ,making a clean gas.

According to the present invention, I combine an initial gasification stage of a character which producescleangas, with a second gasification stage which completes the consumption of the fuel which is not gasified in the first stage, the

two stages of gasificationtherefore cooperating to make it possible to obtain a clean gas without using any undue excess of air, or incompletely consuming the fuel.

Preferably, in the first stage of gasification above mentioned, the fuel is suspended in an upwardly moving gaseous stream to gasify the volatile matter and a portion of the fixed carbon content ofthe fuel, and in the second stage of gasification, fuel particles not gasified in the first stage are collected in a firebed of the producer gas type, and ther gasification completed. The firebed above mentioned is preferably located beneath and adjacent the first stage of gasification whereby the heat and hot gases produced in the second stage assist in maintaining good gasifying conditions in the first .stage as hereinafter described in greater detail.

However, in a broader aspect of the invention, it will be apparent from what is stated above, that the first stage of gasification may involve a firebed either of the underfed or down-draft type, which will also produce a clean gas, and from which the incompletely consumed fuel may be conducted to the second stage of gasification as above outlined. In fact, in the hereinafter described forms of the first gasification stage wherein the fuel is suspended in a gaseous stream as above mentioned, the fuel is fed in from below, and the underfeed principle firebed is therefore utilized.

The present application contains certain subject matter disclosed in my Patent No. 1,812,080, June 30, 1931, entitled Method and apparatus for burning granulated coal, and also certain subject matter disclosed in my Patent No. 1,722,496, July 30, 1929, entitled Boiler and method of operating the same.

Another object of the invention is to increase the efficiency of the present process of gassifying tarry fuels, by producing a gas so free of tar that a substantial portion of the sensible heat of such gas may be extracted and utilized without clogging up the heat exchange passages employed for this purpose.

Certain apparatus is shown and described herein for carying out the invention but the description should be considered as merely illustrative of the principles of the invention.

In the drawings,

Fig. 1 is a central longitudinal sectional view showing apparatus operative in accordance with the invention.

Fig. 2 is a horizontal section taken on line 2-2 of Fig. 1.

Fig. 3 is a view similar to Fig. 2 but taken on line 33 of Fig. 1.

Fig. 4 is a View similar to Fig. l but showing a modified form of apparatus.

Fig. 5 is a detailed section taken on line 5--5 of Fig. 4 looking in the direction of the arrows.

The form of apparatus described in Figs. 1 to 3 is designed more particularly for the manufacture of producer gas but likewise may be operated to complete the combustion of the fuel by supplying air in larger proportions, or to make oil producer gas, in which latter case the oil spray nozzle is located higher up in the throat.

In the form of apparatus illustrated in Figs. 1 to 3, the initial stage of gasification takes place in an upstanding chamber 3'7 which is enclosed by annular members 38 and 39 of suitable refractory material such as carborundum, the chamber being preferably provided with a somewhat restricted throat 40 at its bottom.

The members 38 and 39 may be supported as shown by means of brackets 41 extending inwardly from a water-jacketed section 42 of the outer wall 43 of the apparatus.

the bottom of pipe 44 from underneath,,thus ascuring that the delivery end of pipe 48 will be kept full of fuel by gravity.

A nozzle 49 may also be employed-in connection with pipe 44, for example to project oil up into throat 40 to supply heat for starting the apparatus in operation, or to supply a certain amount of steam during the operation of the apparatus.

The second stage of gasification, in the'ap'paratus of Figs. 1 to 3, takes place in an auxiliary gasification chamber 50 disposed beneath and in communication with the throat 40 of gasification chamber 37, a firebed supporting'mernber 51 being provided at the bottom of chamber 50, and the air blast pipe 44 coming up centrally through the member 51.

An annular member 52'having its top-closed surrounds the member 38 above described and is spaced from the latter so as to'provide an annular gas passageway 53 which surrounds chamber 37 and conducts the gases issuing frorn'the top of chamber 3'? downwardly in reverse direction to auxiliary gasification'chamber 50'. In passing from chamber 37 to passageway 53 the gases go through aturbuiency chamber 54, which destroys any local stream lines, eddies or dead spots in the travel of the gases.

After reaching the auxiliary gasifi'cation chamber 50 the gases again reverse their direction of travel to pass upwardly through an annular exit passageway 55 located between the member 52 and the outer wall 43 of the apparatus.

In the apparatus as shown in Fig. 1, the member 52 is provided with lugs 61 which space this member properly from wall 43, so as to form passageway 55, and the member 38 is provided with similar lugs 62 which space it properly fromthe inside of member 52, the latter being supported from the outer wall of the apparatus by internal ledges 63 similar to the parts 41 previously described.

The above construction leaves the parts of the apparatus free to slide up and down relative to each other, in response to temperature changes, without setting up injurious'stresses.

In the operation of the apparatus a substantial portion of the fuel particles will be gasified in chamber 37 and the remaining fuel particles will fall on to the firebed 56, and be gasified in this latter stage of the gasification process. The reversal in the direction of travel of the gases in chamber 50 as above described, assists in throwing down on to the firebed 55, unconsumed particles of fuel which are carried along through passageway 53 with the gases issuing from chamber 37, the gases finally passing out through offtake conduit 90. I prefer to maintain producer gas-making conditions in the firebed 56 by employing a deep firebed and supplying only a limited amount of air thereto and the hot combustible gases rising from the firebed will be drawn into the throat 40 by the blast of air issuing from pipe 44 to assist in maintaining gasifying temperature in chamber 37.

In operation air will be supplied to chamber 37 in a quantity sufficient to produce CO from the volatile matter and a substantial portion of the fixed carbon content of the fuel, particularly the finer fuel particles will be gasified under conditions which will produce a substantially tar-free gas. The gasification of the remaining fixed carbon content of the fuel is completed in firebed 56 as above stated, the resulting gas being drawn in through throat 40: by the air-blast passing up through pipe 44, thus mingling these gases produced in the second stage of gasification with those produced in the first stage.

The two stages of gasification thus are adapted togasify successively fine and coarse fuel particles, making it possible to use bituminous coal which has only been subjected to a relatively cheap "crushing operation, and avoiding the expense of reducing the coal to the usual fine and uniform state of pulverization.

In theoperation of the form of the invention shown in Fig. 1 the turbulency chamber 54 assists in bringing the fuel and' air-into that close contact-and intimate mixture which is necessary to good gasification, and; materially reduces-the height of the apparatus'which otherwise would'be'necessary.

The slag or agglomerated'fuel particles-which may form in chamber 37," may dropout of: the chamber'through throat 40 on tofirebed 56, the throat being made somewhat larger in diameter than-pipe 44-fcr this purpose, as well as to afford an entrance passageway tochamber 37 forthe gasesdeveloped from firebed 56;

The firebed- 56' preferably is mechanically agitated from underneath to assist in maintaining uniform-gasifying conditions throughout the firebed. As shown; the agitation is effected by rotating the firebed' supporting member 51, and providing this member with a plurality of ribs 5'7 and 58 (Fig. 3), which twist'through the bottom. of the-firebed and'undulate it from underneath, as well as stroke out the-ash-from the bottom of the firebed through anannular ash opening 58, after which the ash may 'drop' down to a gas-tight ash chamber 59-located at the bottom of the apparatus. Thenecessary air for'consumingthe firebed 56 may beobtained through a pipe 60 in chamber 59-from which the air flows upwardly into the firebed through the-ash opening 58.

As shown, the firebed supporting member 51 is carried by rollers 64 and rotated by a gear 65 engaging teeth on its underside.

The above-apparatus is-symmetrically disposed with regardto its central vertical axis, which avoids uneven temperature conditions in the firebed and also promotes uniformity ofthe-gasification operations to a substantial extent.

In the form of apparatus illustrated in Fig. 4 the first stage of gasification is carried out in a gasification chamber 66, supported upon ledges 6'7 extending from the side wall 68'0f'the apparatus.

Air and fuel are projected up into'chamber 66 from beneath, through pipe 67 in a manner similar'to that above described in connection with Figs. 1' to 3, to gasify the volatile matter and a portion of the fixed. carbon content of the fuel. In this instance the gaseous stream reverses its directionof travel in the upper end of the chamber 66 and passes down alongthe walls of the latter, the upper end of the chamber serving to create turbulency as above described.

After passing out at-the bottom of chamber 66 the gaseous stream reverses its direction to throw out unconsumed fuel on to a firebed 68 similarto the firebed 56-previously described, the

gases then passing upwardly through an annular exit passageway 69 interposed between chamber 66 and the sidewalls 68 of the apparatus, to the off-take conduit 91.

A certain amount of the gas developed by the firebed 68 will be drawn up into chamber 66 by the air blast passing through pipe 67, the remaining gas so developed mixing with the gas developed in chamber 66 to pass out through exit passageway 69.

As shown in Fig. 4 the air blast passing up through pipe 67 is preheated in a portion of the pipe Which passes through firebed 68 and also by means of a jacket 70 which surrounds the metallic sidewall 71 of firebed 68, through which jacket the air is led prior to entering pipe 67.

As shown, the firebed 68 is supported mainly by a stationary annular member '72 which projects down into a rotary Water cooled trough '73, which latter in conjunction with an annular lip 74 projecting down from the firebed enclosing Wall 71, affords a water-seal for the interior of the apparatus,

A certain amount of the air required for gasification in firebed 68 may be supplied by a pipe 75 which is connected to the jacket 70, preferably in a manner illustrated in Fig. 5, so that the distribution of the air between pipe 67 and 75 may be regulated by a damper 76. As shown, the pipe '75 leads to an annular blast chamber '77 beneath the firebed 68 and surrounding pipe 67, the blast entering the firebed through central air ports 78.

If desired, air may also be supplied at the peripheral portion of the firebed, as by providing holes '79, adjustable by dampers 80, which lead from air jacket '70 to an annular blast chamber 81 enclosed by the annular lip 74, the blast passing into the bottom of the firebed through blast openings 82.

Fuel may be fed to pipe 67 in any suitable manner as by means of a feed screw 85 which forces the fuel through a pipe 86 connected to pipe 67.

While the invention has been described as carried out by means of certain specific apparatus, it should be understood that many changes may be made without departing therefrom, as set forth in the appended claims.

I claim:

1. An apparatus for consuming finely divided fuel, including means providing an upstanding gasification chamber, means for projecting an air blast upwardly into said chamber to supply to and suspend fuel therein, said apparatus having means providing a return gas passageway communicating with the upper portion of said chamber and extending downwardly therefrom, and means for maintaining a firebed in communication with the bottom of said chamber and also in communication with said passageway.

2. An apparatus for consuming finely divided fuel including means providing an upstanding gasification chamber, means for projecting an air blast upwardly into said chamber to supply to and suspend fuel therein, a dome-like member surrounding the upper portion of said chamber and spaced therefrom to provide a downwardly extending gas passageway communicating with the upper portion of said chamber, and means for maintaining a firebed beneath and in communication with said chamber and passageway.

3. An apparatus for consuming finely divided fuel including means providing an upstanding gasification chamber, means for projecting an air blast upwardly into said chamber to supply to and suspend fuel therein, a dome-like member surrounding the upper portion of said chamber and spaced therefrom to provide a downwardly extending gas passageway communicating with the upper portion of said chamber, and means for maintaining a firebed beneath and in communication with said chamber and passageway, said apparatus having means providing an annular exit gas passageway surrounding and leading upwardly with regard to said dome-like member.

4. An apparatus for consuming finely divided fuel, including means providing an upstanding gasification chamber, means for projecting an air blast upwardly into said chamber to supply to and suspend fuel therein, said apparatus having a return gas passageway communicating with the upper portion of said chamber and extending downwardly therefrom and means for maintaining a firebed in communication with the bottom of said chamber and also in communication with said passageway, said apparatus having a turbulency chamber interposed between said first mentioned chamber and said passageway.

WILLIAM B. CHAPMAN. 

